LONDON (USA TODAY)- In the world of sports, fans relish the heated rivalry - sometimes live for it. Yankees-Red Sox. Cowboys-Redskins. Canadiens-Bruins. Lakers-Celtics.

But USA-China?

Americans who remember the USA-Soviet Olympic battles during the Cold War might shrug at this rising threat on the athletic stage, but over the last dozen years - heating up in 2008 in Beijing and gaining strength this summer in London - Chinese athletes have become the greatest challenge to American dominance.

Indeed, on Thursday night, as the sun set over Olympic Park, the medals race was on between the United States and China.

At the Aquatics Centre, China's dominant diving team was making a splash. Just across the park, the USA's star-spangled track team was making its own statement of superiority. Two Olympic superpowers, flexing before the global crowd.

The USA likely will finish atop the medals table, just as the Americans have done in the previous four Summer Games. With three days of competition remaining before Sunday's closing ceremony, the USA leads China 90-80 in the overall medal race. However, the gold medal duel is too close to call. The USA had 39 golds compared with China's 37 through Thursday.

"The Olympic Games is a competition between athletes, not nations," USOC chief executive officer Scott Blackmun wrote in an e-mail Thursday before watching the U.S. women's soccer team's 2-1 victory against Japan - securing the gold. "With that said, we are very proud of our American athletes in London."

Taking a more modest approach into the Olympics, the USOC didn't set a public goal for medals as it had in recent Games. But with 63 events remaining - 15 of those in track and field, a sport in which the USA excels - the medal title is again within reach.

China traditionally dominates diving, table tennis and badminton - sports that had mostly wrapped up before the final weekend. In the Games' final days, the USA likely will continue to pile up medals in track and field and basketball.

On Thursday, this story line rang true. The Americans won four medals in track, the gold and the silver in both decathlon and men's triple jump. In diving, China continued its dominance as Chen Ruolin won the 10-meter platform by 55.80 points, a blowout. China has won six of seven diving gold medals, with only the men's platform event remaining.

"I just hope the Chinese can get more gold," Chen said through an interpreter. Then she smiled. "The more the merrier."

As he watched the medals ceremony, Renzhong Ran cheered for Chen since no Americans advanced to the 12-diver final. Ran, a 21-year-old student at the University of Texas, was born in China. His parents immigrated in the mid-1990s, and Ran grew up in Corpus Christi.

"I check the medal count every night to see how things are going," said Ran, wearing a red USA T-shirt. "But I don't see the medal count as important. We're not competing in the same events. Both countries are dominating in their own sports."

'We're pulling for you'

At the taekwondo venue Thursday, Joe Lyons of Chicago was wearing blue pants covered with white stars. His white jersey said "United States of America."

"It's just a national pride thing," said Lyons, 34. "China focused so much on other sports last time in Beijing. They got their kids to do rowing and all these other things they'd never done before. It's just obviously national pride. Everybody wants to get more golds. And everybody I've met here - the Irish and the English - they're like, 'Hey, we're pulling for you over China.' "

In London's bustling Chinatown, decorative red lanterns hover over the narrow streets. Here there is growing interest in China's Olympic medal fortunes. Jack Teng, a cashier at a local hair salon, recently started stocking Chinese flags. They've been selling briskly, he said.

"People want to show the flag with the team doing well," said Teng, 17, who is Malaysian.

Leong Chun, a 29-year-old waiter, checks his cellphone at least twice a day to keep up with Team China and the latest medal count. "We would be very happy if we had more than the United States because they are a big team." The USA brought 530 athletes; China has 396.

Mostly any discussion of international rivalry was eclipsed by national pride. "We just want to be No. 1," said Jessica Liu, a cashier at an herbal medicine shop. "But it really doesn't matter which country we beat."

Cheong Lao, 52, said the "spirit of the games" is what matters most. And if China stands atop the medal standings at the end, "I will be very proud."

Beyond the Games

The intense USA-China competition that the world has witnessed on London's Olympic stage is simply a microcosm of the ongoing USA-China duel over global affairs.

The head-to-heads over these meatier matters include sparring over trade, human rights and military positioning, among other things. Though President Richard Nixon's historic trip to China in 1972 began to thaw the cold relations between the two powers, the ensuing 40 years has been a bumpy ride: the Tiananmen Square massacre in 1989, normalized trade relations in 2000, a spy-plane standoff during the early months of President George W. Bush's administration.

The past decade in particular has seen China building its military while becoming the United States' largest foreign creditor, cementing the fiscal interdependence of the two countries.

In London, however, these issues were merely the unseen and perhaps unspoken backdrop. The focus in these Games, and surely emerging from them, will be whether the Chinese will overtake the USA by continuing to make inroads in sports Americans have traditionally excelled in. Take swimming, for instance.

The Americans dominated the swimming events, like they usually do, winning 30 medals. But China served notice, grabbing five gold medals compared with one gold four years earlier.

Olympic historian Bill Mallon cites the "Olympic bounce" factor as the reason why the host nation usually receives a medals bump even four years later. If China's success in the pool continues, the swimming competition in the 2016 Olympics in Rio de Janeiro could be full of drama.

Just after China's first female swimming gold medalist of the Games, Ye Shiwen, got out of the pool, the whispers started. The 16-year-old had broken the world record in the 400-meter individual medley, and suspicions about the use of performance-enhancing drugs began to spread. Ye won gold in the 200 individual medley later that week, fueling the speculation.

The attention centered on Ye's final 50 meters of her freestyle leg in the 400 IM, which she swam at a faster pace than American Ryan Lochte, who won gold in the men's 400 IM.

"History in our sport will tell you that every time we see something, and I will put quotation marks around this, 'unbelievable,' history shows us that it turns out later on there was doping involved," executive director of the World Swimming Coaches Association John Leonard told U.K.'s The Telegraph.

Ye said she did not cheat, had never failed a drug test and blamed the Western news media for attacking her because she is Chinese.

"Until we know more in this situation, I think we should not (make accusations)," U.S. men's swimming coach Bob Bowman said. "People who are reacting went through the '90s when there definitely was an issue and it was proven.

"That's something (Chinese swimmers are) going to have to overcome."

Bowman said he felt China is a rising power in the swimming world because the country has a large population and has taken an interest in developing a successful swimming program. He also said he thinks the Chinese want to beat the USA in swimming and in the medal count.

"I think that's always their goal," Bowman said. "They've gone for years more isolationist, and now they're more part of the global community. They want to be a big part of it."

Unlike every major governing body, the USOC receives no federal funding. A decade ago, China began Project 119, using state resources to fund training for athletes in sports which China traditionally hasn't succeeded in - swimming, gymnastics and track and field.

Medals on their minds

Four years after the 2008 Olympics, the Beijing Games still have a hold on China. "I watch the Olympic Games almost every day," says Tian Ye, 27, a photographer in Beijing. "I will be watching it tonight."

Olympic news is prominent on the front pages of state-controlled newspapers daily and on nightly broadcasts on CCTV. The praise has been effusive - even when an athlete falters.

With an American flag wrapped around his body at Olympic Park, Chris Lau, from Hoboken, N.J., said the medal race is not on his radar in part because NBC focuses on feature stories, not the medal count.

Then there are other fans who root against China because of the medal race. At beach volleyball on Wednesday, Brazil met China in the bronze medal game. Said Skylar Dorosin of Palo Alto, Calif., "At first, we were like, 'Who are we going to cheer for?' Then we were like, 'No! We've got to get rid of one (more potential) Chinese medal.' We went crazy for Brazil."